×

Detection of low noise frequencies for multiple frequency sensor panel stimulation

  • US 20080309628A1
  • Filed: 06/13/2007
  • Published: 12/18/2008
  • Est. Priority Date: 06/13/2007
  • Status: Active Grant
First Claim
Patent Images

1. A method for determining low noise stimulation frequencies for use in generating an image of touch from a touch sensor panel, comprising:

  • while applying no stimulation frequency to any of a plurality of drive lines in the touch sensor panel, receiving a noise signal from each of a plurality of sense lines in the touch sensor panel into a charge amplifier of a different sense channel;

    summing an output of all charge amplifiers to generate a combined noise signal;

    demodulating the combined noise signal with in-phase (I) and quadrature (Q) components of a first plurality of frequencies;

    for each of the first plurality of frequencies, accumulating the I and Q components of the demodulated noise signal and generating a noise value for that frequency by calculating a magnitude of the accumulated I and Q components of the demodulated noise signal; and

    determining the low noise frequencies by selecting those frequencies whose generated noise values are smallest.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×